The development and application of an underwater

The development and application of a new detection system is described for autonomously working radioactivity measurements, usable in seawater and river environment. The system is based on a NaI scintillator with specifications for use in the marine environment and for real time acquisition. It is simple, stable for long-term monitoring, and of low consumption. The sensor was energy and efficiency calibrated in the laboratory. Many tests were made for the linearity and the stability of the electronics. The energy resolution calibration of the sensor was performed prior to its location into the tank, using various reference point sources. The system was deployed in open sea in order to measure background and low volumetric activity of 137Cs (19 Bq/m3). The field measurements in the Aegean Sea offer very promising results concerning the use of the whole system in the marine environment to be used as continuous monitoring and alarm system

A marine groundwater spring in Stoupa, Greece: Shallow water instrumentation comparing radon and ambient sound with discharge rate

AbstractThis work describes the combination of two autonomous in-situ systems, one using the measurements of radon progenies and the other one using underwater ambient sound, for monitoring submarine groundwater discharge (SGD). The sensors were co-located on a platform and deployed in a SGD point source at Stoupa, Messinia, Greece. Long-term monitoring of radon progenies concentration as well as acoustic measurements are presented. The radon progeny data were correlated with the flow rate during one of the deployments. The ambient sound levels apparently responded to changes in the physical structure of the spring, but not in a predictable manner. The measuring platform can be easily applied to oceanographic survey activities, such as monitoring of gases and fluxes on submarine groundwater discharges, pockmarks, volcanoes, submarine faults, as well as to the measurement of rainfall freshwater flux at the ocean surface